Genes Direct Protein Production (finished)

• Cell division: process of creating two daughter cells from a parent cell
• Cell differentiation: process by which a cell acquires its specialized functions
• Gene expression: process by which genetic material is used to drive cellular functions
• Morphogen: a signaling factor that directs cell fate at a distance from their source of production
• Indictive Signaling: process through which a cell or group of cells secretes factors that influence neighboring cells
• Regional determination: once embryonic tissues reach a certain stage of development they are committed form their adult structures independent of their environment
• Gastrulation: process by which the bilaminar embryonic disc becomes the three key germ cell layers needed to generate all the tissues/organs in the body
• Neural crest cells: embryonic cell populations that are formed between the developing neural tube and the epidermis

  • Cells migrate along very specific restricted pathways (routes) to give rise to many of the craniofacial structure (and other tissues)
• Hox genes: specialized set of genes that contain a homeodomain motif (homeobox) that carry permanent record of positional information used to specify patterning
• Cells achieve their specialized functions based on:

  • Expression of specific genes
  • Expression of any subsequent post-translational modification of resulting proteins
• DNA is transcribed into RNA
• RNA is translated into proteins
• Every gene in humans can have 8 different proteins
• Different proteins can be targets for drugs
• Cells use transient mRNA as an intermediary to help gain finer control over the expression of proteins
• mRNA can be degraded quickly
• In prokaryotes and eukaryotes, gene transcription can proceed in opposite directs from one gene to the next
• RNA is made in the 5'->3' direction

  DNA template strand is oriented in the 3'->5' direction
• Untranslated regions (UTRs) don't encode proteins
• If mRNA is degraded before it leaves the nucleus or is unstable, no protein is being made
• RNA that matches mRNA can be used to create double-stranded RNA

  • Can silence protein
  • Used in lab and in nature
  • Doesn't occur often
• Eukaryotic transcription can have more specialized proteins/cells because it is a more complex process with different ways for cells to control what proteins are made and when
• The more genes that are available for transcription, the less differentiated the cell is
• Older people have fewer pluripotent cells
• If splicing mechanism is broken, there would be less proteins being made and it would be a slower process
• Gene: fundamental unit of heredity that is a sequence of DNA that's transcribed into RNA and its associated transcriptional control regions
• Capping and polyadenylation are necessary to form mature mRNA in eukaryotes
• Transcription factors are what is enacted by endogenous and exogenous forces to tell cells to make or not make proteins
• mRNA (messenger RNA): is translated into proteins

  • Makes up ~3-5% of RNA in body
• tRNA (transfer RNA): transfer amino acids to the growing peptide chain

  • Makes up ~15% of RNA in body
• rRNA (ribosomal RNA): encoes ribosomal proteins

  • Makes up ~80% of RNA in body
• microRNA: block translation of specific mRNAs and regulate gene expression
• siRNA (small interfering RNA): turn off gene expression by directing selective degradation of mRNA
• snoRNA (small nucleolar RNA): process and chemically modify rRNAs
• scaRNA (small cajal RNA): modify snoRNA and snRNA
• other noncoding RNA: involved in telomere synthesis, x-chromosome inactivation, and protein transport into the endoplasmic reticulum
• Telomeres: on the ends of chromosomes that keep them from fraying apart
• The older you get, the shorter telomeres are
• Color blindness: gene is present on X chromosome

  • Men have a greater chance of being color blind than women because women have 2 X chromosomes
• Most protein coding genes are transcribed by RNA polymerase II